Trim corrector control devices of vehicles



United States Patent Inventor Jacques Remaud,

Billancourt, France Appl. No. 702,428

Filed Feb. 1, 1968 Patented Nov. 10, 1970 Assignee Regie Nationale Des Usines Renault,

Billancourt (Hauts de Seine) and Automobiles Peugeot, Paris, France Priority Feb. 15, 1967 France 95,089

TRIM CORRECTOR CONTROL DEVICES 0F VEHICLES 11 Claims, 4 Drawing Figs.

U.S. Cl. 280/104, 180/41, ZOO/61.52, 280/6, 280/124 Int. Cl. 860g 21/06 Field of Search 280/6, 6.1 1, 124(F),104; 180/41 [56] References Cited UNITED STATES PATENTS 2,911,230 11/1959 Peras 280/104 3,157,413 11/1964 Alfieri.... 280/124(F) 3,194,579 7/1965 Peras 280/104 Primary Examiner-A. Harry Levy Attorney-Stevens, Davis, Miller & Mosher ABSTRACT: A device for front and rear wheel suspensions of an automotive vehicle having trim col-rectors of the hydraulic and/or pneumatic type, comprising a reservoir containing a hydraulic mass of relatively great inertia and a partition dividing the reservoir into two compartments and adapted to pivot about an axis in case of acceleration or deceleration of the vehicle and in response to the movement of said hydraulic mass. Signal transmitters mounted on the reservoir are actuated by the movement of the partition and control the trim correctors by means of valves.

Patented Nov. 10, 1 970 Sheet INVENTOR JACQUES REMAUD BY v mammww ATTORNEYS I TRIM coiiitEc'r'oR cosmo advices-or viinc'niris This invention relates to means for sup ressing any dvercoircction ofthe trimof an automotive vehicle dur'iiig ecceier s iions and decelerations or brake applications. p

It is known that in vehicles equipped with particularly fle'iti blc suspension systems with trim cori'ec'toii's; stitch as deserihed and illustrated iii the us. Pcie'iit Ne. 3 iqcsis issued to Lu:-

cich Pcras Oli July 3. i965 driving accei'eia ct decelerations are ti tehded by the addition of extra dad to the rear wheels or the front wheelsof the vehicle, thus altering: the trim thereof. This modification in the vehicle tririi: is all the; thosepronounced in the case of a high-flexibility uspension system.

In fact, if ne considers as ah e iai-hp e adeoeleration period in excess of 3 to 4.secoiids,,i.e-. the timelag introduced in the correction, and an acceleration following immediately this deceler'ation,- as freqtieritly ohser ved in the case of a vehicle approaching red traffic lights chahgirigto gr'enbet'ore the vehicle has stopped completely as cechsequeiiee of the heees= sary brake applicatiori-, so that a sudden acceleration takes place, the following phases take place:

a. first, a deceleration period caused by the Brake application, involving an increasedlo'adori the fiont of the vein-- cle which is thiis lowered while the rear is raised; v

. after a fewseconds, the trim corr'etor becomes operative, thus reinflating the front suspension by increasing its pressure, and unloading the rear-suspension by'redticing its pressure, so that the vehicle recover's'its normal posi tioh; and 4 subjected to the additional load caused by the brake application, it rears up; this movement is further acceritu at e'cl if the vehicle is accelerated; thtis causing additional load to be applied on th'e' rear thereof. This last phase is alsoohserv'ed in there'verse case, the. when an acceleration is followed by a-hrake applica ion.

. upon release of the brahe pedal as the vehicle is h morc FIG.. 1 inustratesa first form cf'embodiiheht of the device of trated' in F'lGL. I; and

Drivinga vehicle, especially in town traffic conditions, is I thus a cause of particular discomfort due on-the one hand to the very frequent changes in the vehicle trim and on the other hand to the fact that the suspension system i'ssometirnes fully deflected to its stops and'becorn'e's abnormally stiff;

Another inconveniehceari'sing witha knowt'i'typ'e of'triin corrector liesin the fact that the, fluid-distributor and more particularly the pump hedcihe operative. each time the vehicle is decelerated' by releasing the accelerator pedal/oraccelerated by depressing this pedal; which, notinention the noise resulting therefrom, is detrimental to the useful life of the parts involved.

it is the essential object'of the present invention to provide an inertia-controlled device capable of avoiding thesevarious inconveniences as well as overcori'ectiori's of the vehicle trim during alternate acceleration and deceleration phases the pump, the distributor and the member's assoeiatedth'erewith being allowed to restore the" proper trim only iii-ease of actual change in the load and also for'conipen'sa'ting any deflection of the vehicle which might be c'ati's'ed by leaks-in'the general characterized by the, provision of'a reservoir containin a high-inertia hydraulic mass in two compartments separated bya central partition adapted tohe deflected by said hydraulic mass in case of acceleration or deceleration of thevehicle' for actuating means capable of transmitting signals controlling the members acting upon said trim correcting elements.

Other. features and advantages of this in'ven on will appear more clearly as the following description proceeds with reference to the attached drawing illustrating diagrammatically by way of example two t pical form's-of embodiment of the invention, it being uiideistccd that various modifications and variations maybe iii-ought thereto without departing fromthe spirit and scope of the invention as setforth in the appended claims.

In the drawing? H6. 4 illustrates in diagrammatic formthe connection between theldevi'ce of H6. 1 and a known trirn-correcting device. v i

The device shownin FIG. I comprises-a reservoir I of substatttially rectangular configuration, filled with a suitable fluid such as oil H divided by a central partition 2 into two volumes, [.e. a r'ear fluid volume A and a front fluid volume B, these vdiuhies-heih iden ical under normal driving conditions. The central partition 2. is adapted to oscillate about a pivot pin 3 secured to the walls of the reservoir and comprises an exten sion 4 beyond the upper edge of the reservoir 1, which is closed by a cover 5 The central portion of the bottom of reservoir I is of suhstantiall'y cylindrical configuration with a radiiis corresponding to the'height of said partition ibetw'e'e'n its pivot axis 3 and thebottorn 6. Spring rneans 7 secured to the underface' of co'v'er 5 clampthe upper portion of partition I Ito urge same in its median position. shown in thickiines. In-

ertia weights 8 are secured to the projecting upper extension 4 of partition 2, theiipur'pose consisting in so balancing the partiti'on that it cannot be infl'uenced bythe accelerations of the vehicle or By the gradient on which the vehicle may be paralieh-their hicv'ahie cciitact arms 10, for example are 'groundedand the fixed contacts. 10, are connected'to one'end of the winding 12of a-three=way solenoid valve 13. The other end of windingli iscdhnected to'one terminal of a battery 14 having its other terminal grounded.

The core i winding 12" of said solenoid valve i's'r'igid with the rod l6'of a' valve I7Tur'ged by a spring to the position illustrated inFl G. 2 in the. deenergized condition of said. winding. In this case the'valve 17 'closes the communication between the port connected to the corrector' circuit and the port 20-,

'comrniinica'tingwiththe. atmosphere; however, the valve 17 permits a free-communication between ports-l9 and 21, the latterb'eing con'nected't'o the vacuum circuit permitting the operation of the corrected The energizatidn of winding 12 causesthescorelito beattracted in the direction of the arrow f to isolate. port '21;

A-third front contact 221 actuated hy the brake pedal 23 is mounted in parallel with contacts 10, its movable contact arm 22; iseonne'cted to thesolenoidw winding l2'and its fixed cont'act 22', i's gr'ounded.

The-above descrihed arrangement operates 'asfollows:

D'Uring'the acceleratiomperiods, the oil subjected to he resulting pressurei's moved, its level changing from A to A "or. B to 8; due to the oil pressure the movable partition 2 pivots]- about its axis 3 and compresses one of the springs 7 to engage one of the stops 9 and close one of the contacts 10.

vUriclerthese conditions the solenoid valve 13 is energized and alve 17'closes the communication between port '19 and port-2i cch'nected to the vacuum circuit, whereby on the one trim of the vehicle is restored.

If the vehicle is on a pronounced gradient, the oil, by gravity, will exert a pressure on partition 2 and thus eliminate any correction possibility, but due to the provision of a gaged orifice 24 in partition 2 after a certain time period the oil will be at the same level on either side of the partition, the latter being then in its intermediate position; thus, the trim correction can take place again. Therefore, this correction is not disturbed by the fact that the vehicle is on a gradient, and the suspension cylinders can be reactuated normally.

If the vehicle is stopped after a long brake application, for example on a slope, which implies that the driver keeps the brake pedal depressed, the device will operate as follows, in the absence of any signal contact on the brake pedal:

a. during the brake application period, the device would prevent any correction, but the vehicle would not have its normal trim, since the additional load on the front wheel would cause it to bow;

b. once the vehicle has been brought to a standstill, if the foot pressure is maintained on the brake pedal, the positive action of the brakeshoes would prevent the vehicle from resuming its normal trim. As the oil H contained in the reservoir 1 is no more subjected to an acceleration and leaves the central partition 2 undisturbed, the trim corrector would be allowed to operate. It would even operate beyond the necessary limit since the resumption of the vehicle trim would be retarded by the action of the rear brakes. Then, upon release of the brakes, the vehicle would rcar abnormally This inconvenience is avoided by the provision of the brake pedal contact 22 which eliminates any possibility of trim correction when the brakes are applied.

Since the operation of the device according to this invention is based on the force of inertia of the oil mass, it is clear that this device will also be operative during deceleration periods due to engine braking.

in the modified form of embodiment illustrated in FIG. 3 the partition 25 is reinforced by transverse ribs 26. Its lower portion is attached by an anchor member 27 to the flat bottom of reservoir 1; the upper portion 28 of this partition is free and spring means 29 constantly urge same to the vertical in the normal position of the vehicle.

The upper edge' 28 of partition 25 engages a piston 30 which, being allowed to move downwards when the partition is deflected by the action of the hydraulic masses as shown by the dash-and-dot line, releases the control member 31 of a switch 32 which maintains a pushbutton of said switch in a position where the switch is open. The releasing of the control member 31 permits the switch to close an electric circuit. This switch is housed in a case 33 rigid with the cover 34 of reservoir 1, this case 33 being closed in turn by a cover 35 through which conductors 36 connect the switch 32 to the control solenoid valve.

The device illustrated in FIG. 3 operates exactly like the one described hereinabove with reference to FIGS. 1 and 2.

In these examples the signal is transmitted electrically, but it would not constitute a departure from the spirit and scope of the invention to use pneumatic, hydraulic or mechanical means for transmitting the corresponding signal to a suitable control member or device.

The present invention can be used advantageously, e.g'., in a vehicle attitude-correcting device such as the one shown in U.S. Pat. No. 3,374,848, issued Mar. 26, 1968, to Gaetan de Castelet. This device, as shown diagrammatically in FIG. 4, comprises a hydraulic distributor 105 connected on one hand to a source of pressurized fluid (not shown) and on the other hand to a valve 108 of a front ,wheel suspension 102. Valves 108 and 109, together with a manually controlled selector valve 110 constitute a trim corrector device permitting different ground clearances for the suspension. Each of .the

valves 108 and 109 is associated to a wheel arm 104 pivotally fixed to the vehicle chassis 101. Each suspension 102 or 103 comprises a hydraulic cylinder C associated to a hydropneumatic element A. intermediate to wheel arm 104 and the chassis 101.

The threesway valve 13 of the present invention device is inserted between the manually controlled valve and the vehicle engineinlet tract 66, constituting a depression source,

in such a manner that the port 19 is connected to the valve 110 and the"port 21 to the inlet tract 66. The valve 13 thus controls the pressure fluid flow in'the trim corrector device.

Iclaim:

1. A device for avoiding overcorrection of the trim of a vehicle by fluid actuated trim correctors for the front and rear wheel suspensions during periods of acceleration and braking of the vehicle comprising a source of fluid pressure for said trim correctors, a reservoir containing a hydraulic mass of relatively great inertia, partition means dividing said reservoir into two compartments, means mounting said partition for movement selectively by said hydraulic mass in response to acceleration and braking of the vehicle, means connected to said source and trim correctors controlling the flow of fluid from said source to said trim correctors, control signal-transmitting means connected to said control means, and actuating means responsive to the motion of said partition means to actuate said signal-transmitting means for transmitting appropriate control signals to said trim corrector control means.

2. A device according to claim 1 further comprising at least on gauged orifice formed in said movable partition to permit fluid communication between said two compartments.

3. A device according to claim 1 wherein said movable partition is pivotally mounted in said reservoir and includes at least a portion extending out of the reservoir beyond the pivotal axis.

4. A device according to claim 3 wherein said actuating means comprises inertia weight means on said extended portion, said weight means being adapted to actuate said signaltransmitting means.

5. A device according to claim 1 further comprising antagonistic spring means disposed on either side of said movable partition biasing it towards a normal position.

6. A device according to claim 1 further comprising stop means provided in the bottom of said reservoir for limiting the movement of said partition.

7. A device according to claim 1 wherein said fluid flow control means comprises solenoid valve means operatively connected to selectively control the operation of said trim correctors.

8. A device according to claim 1 wherein said control signal transmitting means comprises switch means having movable contact means selectively engageable by said actuating means and at least two fixed contacts connected in parallel and selectively engaged by said movable contact means.

9. A device according to claim 8 further comprising secon switch means connected in parallel with said switch means and actuated by the brake pedal of said vehicle.

10. A device according to claim 1 wherein said movable partition includes transverse ribs and has its bottom end secured to the bottom of said reservoir, the deflection of said partition by said hydraulic mass causing actuation of said signal-transmitting means.

11. A device according to claim 10 wherein said signaltransmitting means comprises a switch mounted at the upper portion of the movable partition, piston means mounted above the free end of said partition means and adapted to maintain said switch in an open condition when said movable partition is in normal position and adapted when lowered as a result of distortion of said movable partition to close said switch. 

